1. Field of the Invention
The present invention relates to a freight car for transporting and storing bulk material, which comprises an elongated frame supported on undercarriages running on a track having a loading gage, an elongated box mounted on the frame for storing the bulk material, the box having two side walls, an open top and a bottom, a conveyor band at the bottom of the box for transporting the stored bulk material, the conveyor band extending in the longitudinal direction of the box and having an input end and an output end, and a transfer conveyor adjoining the conveyor band at the output end, the transfer conveyor extending in the longitudinal direction of the box and being arranged to receive the transported bulk material from the conveyor band, the transfer conveyor having a free discharge end projecting beyond the elongated frame and being pivotal transversely to the longitudinal direction about a vertical axis.
2. Description of the Prior Art
U.S. Pat. No. 4,576,538, dated Mar. 18, 1986, discloses such a freight car and how any desired number of such freight cars may be advantageously coupled together to form a train along whose length bulk material may be transported and transferred from car to car by means of the transfer conveyors projecting from each car to the following car. Such a train may be used, for example, to transport the bulk material coming from a ballast cleaning machine from a rear car towards a lead car, using the bottom conveyor bands to transport the bulk material from an input to an output end within each box and the transfer conveyors to transfer the transported bulk material from the output to the input end of the next car. The free end of each transfer conveyor is detachably connectable with a centering device to the box of the next car adjacent the input end so that the transfer conveyor may be automatically pivoted about a vertical axis in track curves. This centering device assures that the free discharge end of the transfer conveyor is always centered over the box of the next car when the train moves in a track curve. For this purpose, the pivoting drive is kept in a freely floating position so that the centering device will automatically pivot the transfer conveyor in a track curve. The transfer conveyor of the front car is, of course, not connected to a centering device (since there is no car following this front car) and, for reasons of safety, this transfer conveyor is tied to the box to hold it in a substantially centered position and against pivoting about the vertical axis.
European patent No. 10,176, of Nov. 7, 1984, and German Democratic Republic patent No. 73,133, of May 12, 1970, disclose pivotal cranes mounted on a railroad car and equipped with blocking devices limiting the pivoting range of the crane. These patents do not address the problem of preventing an uncontrolled pivoting of a transfer conveyor in a freight car of the hereindescribed type while leaving the transfer conveyor free to pivot in track curves, on the one hand, and stopped in a substantially centered position, on the other hand, when the train is in transit and out of operation.